'Herd' is the word: Developing the Pikmin-inspired The Wild at Heart

Standing out is one of the most difficult things to do in game development. It's incredibly common to be compared to games with similar mechanics that came before, making unique ideas nothing more than the sum of their individual parts.

For Moonlight Kids, creators of the upcoming PC and Xbox One game The Wild at Heart, that meant constantly getting compared to Nintendo's charming real time strategy game, Pikmin.

Instead of trying to shy away from the comparison or wholly embrace it, Moonlight Kids is trying to establish its own subgenre: the "herd-like." The studio wants to a game that uses Pikmin-like elements to create something new.

"With the herd-like, you're not in god-mode. You're still a character that has to interact with the world," said Moonlight Kids programmer Chris Sumsky. "That's what I love about these games, there isn't that fourth level of separation. You're a character in this world but you're still completing higher level strategies."

After playing through the GDC demo of the The Wild at Heart, it's clear that many of the RTS elements were directly inspired by Pikmin. Wake, the games main character, can collect "spritelings" as he runs, throw them at enemies and objects, and have them pick up various tools that can be used at the players campsite. The Wild at Heart adds more to the experience like a crafting system, night time exploration, and a Luigi's Mansion-like vacuum. That's the difference that makes Moonlight Kids believe that they have enough substance for a new subgenre.

"Lemmings is a little more omnipotent, but Overlord might be an example. We're pulling from a lot of different things that aren't Pikmin-related," said Moonlight Kids creative lead Justin Baldwin. "We thought it'd be cool to incorporate those mechanics with building and crafting. There's not a lot like Pikmin out there.

"It has tower defense elements, which still falls under the RTS banner," he added. "You're more grounded by having an actual character in the field, but to put it in broad terms, a herd-like is just controlling an army of things from that point of view."

Sumsky and Baldwin, along with writer Alex Atkins and programming lead Ankit Trivedi, have run into a few issues implementing the specific herd-like mechanics into a 2D space. "Trying to get 2D sprites, 2D animations, and 3D meshes to render and sort in the way we want it is difficult," Sumsky said. "Once you start throwing things around with physics it gets muddled, like throwing a 2D spriteling up against a 3D rock."

"One of the most tangible things we can show people is the editor, a screenshot makes the game look completely 2D," Sumsky added. "If you look at it in the editor you can see its a 3D world with all the 2D assets titled towards at the camera. We're using a prospective camera so we still get this nice bit of parallax when moving the view that also looks 2D."

It was tough to maintain the storybook aethstetic with this type of visual design without making the game look and feel more 3D. The tilted view made the Pikmin mechanics difficult to mix with the games aethstetic. "Throwing a 2D tilted tilted sprite at a 3D cliff face and have it bounce off properly without it clipping through the cliffs is tough," Sumsky said.

The spriteling navigation, which Sumsky highlighted as an important element that makes herd-likes work, wasn't as difficult to nail down. Moonlight Kids used the built-in NavMesh feature in Unity to help the spritelings move and function correctly within the twists and turns of the world. Things like building bridges, climbing up ladders, carrying objects, and whatnot are handled through the NavMesh tool.

"We didn't want to reinvent the wheel with how spriteling navigation works. So we used in-engine functions whenever possible," Trivedi said. "We took the number of spritelings and squared them, making the them as boxy as possible. We keep track of their internal rotation even though it's only a few directions as they are two-dimensional. Once you take their internal rotation into account then you add the box and base it on the player's internal rotation."

The NavMesh system made it easier to implement smooth, reliable spriteling movement. "I've run the game just for fun and put in 200 spriteling followers and gone to a really tiny part of the map where there's a little island and bridge," Sumsky added. "They group very nicely. They follow the shape of the shoreline and the bridge."

Just after starting to tackle the unique challenge of implementing herd-like mechanics into a pseudo 2D space, Moonlight Kids realized that the appeal of a herd-like required a different approach to game development. While other types of games need workable, often rough prototypes to showcase their base gameplay and design, their build needed to do that while capturing the unique, polished appeal of many creatures running around, interacting with the level.

"As soon as we jumped in, one of the things we realized really early on is that part of the pleasure of playing these herd-like games was watching these little guys run around and do things," Sumsky said. "We're gonna need animations for this and that and put a lot of work into the feel of the game, millisecond timings. At one point Justin had static image of these spritelings attacking a wall and the wall was just slowly disappearing which didn't work very well.

"So much of that is polish work," he added. "But it had to be done right away."

That's a frustrating realization to go through as Moonlight Kids has been looking for publishers and other partners. "They want to see the content but we need to put all this time in to make it feel right," Sumsky said. "It feels nice to have something this polished early on, but it wasn't easy to get here."

After showing the game at both GDC in March and Day of the Devs in November of last year, Baldwin and team took the heavy comparisons with Pikmin to heart. Going into both shows they realized the resemblance was there, but didn't think it'd be the main takeaway. They want the herd-like features to be an overlap with Nintendo's classic, not the defining feature.

Those new features include the vacuum and crafting systems as well as other features that haven't been fully developed yet. The team is hoping they can flesh it out more so that the Pikmin similarities aren't the primary takeaway.

"We want it to be bigger. Right now the demo at GDC still feels mostly like Pikmin with a little bit of extra stuff," Sumsky said. "Eventually the world will be bigger and interconnected. It'll almost have this metroidvania vibe where you won't know something is and will have to come back later. One way you'll explore is through collecting spritelings, but other systems will build off that. We want it to feel like something of our own."